Circuit for space discharge lamps



1953 w. c. HALL- ?34 CIRCUIT FOR SPACE DISCHARGE LAMPS FiledMarch 17, 1950 2 Sheets-Sheet 1 IN VEN TOR.

\A/i/Iqrd C. Hall Nov. 10, 1953 w. c. HALL =.v

CIRCUIT FOR SPACE DISCHARGE LAMPS FiledMarch 17, 1950 2 Sheets-:Shqet; z-

6/ V-J6VU 2 INVENTOR. an WI/lard C. Hall Patented Nov. 10, 1953 RAT EN QEEI co -partnershipi;

This". invention: belongs to th'at'-generalclass of devices and methods of efiiciently regulating and operating electric "lighting" circuits" and" 're- I lates: particularly to"*discharge lamp circuits which mayinclude fluorescent'tubular lamps-and the. like. 'The invention has among itspertinent 1 objects the productionof "condenserlesscontrol and operatingspace discharge lamps at a high"- power' factor; "a circuit and included elements which aresimpl'e, durabla and" compact -in' struc- I ture; inexpensive to'make; manufacture and operate; dependable andefficient inuse and service, and'a combinationtha-t is very satisfactory for- I use whenever and wherever found applicable.

Other more specific objects; advantages and features of this particular- 'invention' willappear from" -a careful" perusal=-bf-theaccompanying drawings; "the subjoined detailed description, the preamble of 'thGSGSPBGlfiCatiOIIS; and-"theclaims appended heretow 2O Below,applicantdescribesone of-the-prefer'ableforms-of his invention in order to teach the art thereof and show how to make and use the same; but it is to be understood thatthdrawings and description thereof 'are*not---to limit the -inven-"- tion in any sense whatsoever except as=- the same =-is limitedby the prior art. Language"em ployed herein is not "to be construed as 5 givingany unauthorized person or organizatidn the right to make; use -and7dr *sellthe invention herein disclosed.

Figure =1 is a schematidpla'n view of an electrica-l circuit for starting and operating fiuores= cent lamps and similar -'lighting=devices,-

Figure 1a is a schematic planyiew-of a typical starter switch-for fluorescent lamps,

Figiirefl is another schematic 'planWiew-of another-circuit for starting and operatingspace dischargelamps-andthelike} 40 Figure 3 is another schematicplan' view of still another circuit for starting and operating" space V discharge lamps and the lik'e.

As shown in Figure 1 of the drawings,'-the preferredform of d the invention, an: autotrans-'- 45 former is provided having the coil- -means: 3- and 4 supplied with" a "suitable electric 'current; through thelin'e wires l-and2. .-Theline 'voltag e maybe about 115, butthe coil 4 is of suflicient r turns to Icause a difference in potential :between lines 5 and-l of about 155 volts". By this arrangement,- thecurrent through lines I r and 2 is about l amp. and -the"'current"through line 5 is about 0.84 -amp. t The: line i leads to an: auto-=1 transformercB which -has-a centere point 3|, but-" 55 2 the line '5' is electrically attached totli coil-8 at about five to ten pei'cent' to one-side of the center"? thereof: The grounded" line mak connection" with the autotransfor'mei"'9 at abo'ut five to ten -percentoff-the center 0; this" cOnnec' tionis indicatedatH. p

A pair of fluorescent"lamps,--or"'-any"dther type of discharge" lamp; are'-"sho wn *at-[than each one of the lampshas' a suitableele' l4 at 'each end thereof-i 3 Theseelectrodes ar indicated as of-the preheated"typfbut'cold elerfoi by maki trodes may-- be-'-substituted th certain slight changes to' -'be -herinafte plained; The end conductors f5" and-46 of -=t'h'e autotransformer 9' connect-'with -one s'id of their respective lamp" 'electrodes l l "at the" lower-end of the lamps l2 and I3, as shown; the other side of the lower electrode 14 3 in lafiip' 2 con'nects with a conductor ll; througwa glow' type 'startr switch IBa'nd then*through'condiitonlB te o side of the top-electrode in lampl 2; i Th other side of this top electrode connects with conduct Hand to one'side' of-the primary of a shorted secondary transformer or current regulator J The other side of the primary'makes connection-# with one end of the autotransforin'r The other side of th "lower ele'ctl-bd'e inflame [3 makes connectidn with -the sta1ti' switch- '22 through conductor 23, and the other sid'e of the starter switch 7 make's conn'ectioi'i- -to "oneside the top electrode thr'ough 'conductor 24; The other-side of this latter -electrdde makes (EDIT 0- tion With a current regul'ato r 25 through c 'oridu' tor-26'; this regulator being hortedsecondar" .just-like i i The high Side-OfregUI'atOr 25 makes i connection with one end of the autotra'nsfornier i 8, as shown Between the conductor's fl and-:24 there is connecteda high impedan'ce lamp-start: ing- -reacto'r' 21; 'In the event it is desire o employ cold electrodes #in "place of :the preheated ones shownat l4; then thei switches l8 and? -22 are dispensed with andin place or the 'switch I8 thre is inserted a high impedan'c came-star ing reactor like?! 4 This' wouldnecessitate n I creasing "-the' output' potential 'df the autotran's-- former 3"4-.-

The secondary volt-ampere rating of the lirfe ifi step up transformer is a proximately 1155 volts at omo ampere; under normah conditionsis and the' line current at '--l17 -v olts* is one ampere. The lamp currents wouldbeflfl --each'-and vth' input PIF '90 to*95 It is important to note that the autotransformers connected t'o the" outpi-it of the 5 line autotransforiner "-3 4 are of spe'eial'*de's' ign andperform-"seven? important functions; wit

Coils 8 and 9 may have as much as 10% tap from the center points I and I0, respectively, and this introduces the desired reactance in a balanced manner; and at no-load during the starting cycle, these autotransformers will approximately double the line voltage across autotransformer coil 3 when the impedance reactor 21 is active.

By use of the balancing features of the lamp autotransformers 8 and 9, the discharge lamps l2 and I3 draw equal currents. This arrangement eliminates auxiliary lamp reactors and the core noises and interferences associated with this type of auxiliary reactor or reactors. Applicant employs two specially designed current limiting reactors 2| and 25 that draw an inphase current when series connected as shown. These reactors are small transformers having turn ratios of three to one and values twenty to one or more. The secondary of each reactor is short circuited and its primary in series with its respective lamp, the primary having the greater number of turns and the smaller wire-size. In effect, the current change is considerably greater in'the secondary short circuited winding for a corresponding change in resistance and this may be only a fraction of an ohm for a small change in current in the primary, thus by the principle of reflected resistance, theprimary resistance may be made to change approximately in direct proportion to an increase in voltage applied to the primary, and thus giving a constant current regulation for an increase or decrease in applied voltage. Current density increases in the shortcircuited secondary of each reactor is the same as reducing the circular mill per ampere rating of the secondary winding.

The transformers 2| and 25 may have 126 turns of #27 enameled copper wire for the primary and 43 turns of #25 enameled copper wire for the secondary which is shorted, thus presenting an approximately 3 to 1 ratio when the primary current is 0.420 amp. and hence the secondary current would be 1.26 amps. and the voltage across the primary would be 25.2 volts, the total resist ance by reflection being 60 ohms. core stack of silicon would be used and have a size of in. by in. This is an in-phase regulating means.

The out-of-phase lamp regulating coils total 840 turns of #27 enameled copper wire, the 5% tap being taken at the 440th turn. The silicon shell type core is in. by in. The ratios may vary, however, as the following ratios may be used when control advantages warrant, to wit: l.05/11.l/11.2/1 etc.

The lamp starting reactor 2'! has 3200 turns of #32 enameled copper wire with a D. C. resistance of 150 ohms, and is wound on a /2 in. by A; in. silicon steel shell type of core. This reactor has a very small core and a large number of exciting ampere turns so that when the lamp running voltage is established across the coil (108 volts), the exciting or magnetizing current drops to a very low value, that is, no load the current is 0.750 ampere and under load the current is 0.045 ampere.

Note, in connection with the lamp autotransformers 8 and 9, that the greater the distance from the centers 1 or that the lines and 1, respectively, are equally shifted in opposite directions, the greater is the series impedance introduced in the lamp circuit.

As illustrated in Fig, 2 of the drawings, a similar autotransformer is employed having the coil A shell type 28 across the feed lines 29 and 30, and the series coil 3| which has the lead 32. The line 30 connects with one side of a shorted transformer 33 and from the other side of this transformer is the conductor 34. A pair of lamp autotransformers 35 and 36 having their respective centers at 31 and 38 are provided and their respective taps to their respective conductors32 and 34 are at 39 and 40, as shown, and these taps are about 5% off center, and are indicated by the reference characters 4| and 42, respectively. The heater electrode at, each end of each fluorescent lamp 43 and 44 is connected at the ends of the lamp 'autotransformers, as shown, and bridge volts thereof, each such autotransformer section of coil being indicated by the common numeral 45. A starting impedance 46 is connected across or shunts a pair of electrodes of one of the lamps as shown.

The above arrangement of Fig. 2 at a line voltage of 118, provides a voltage of across lines 30-32 and a current in line 32 of about 0.8 ampere. The electrode to electrode voltage across each lamp is 310 which is sufiicient to start the space discharge. The values of the various elements in this form of the invention is substantially the same as in that of Fig. 1. Note, that no starter switch is needed in this circuit.

Figure 3 shows another circuit which is similar to the basic circuit of Fig. l, but only one lamp 4'! is shown. This lamp has the usual preheated electrodes 48 and 49, one side of which are connected through the switch 50 which may be the well known glow switch. The other sides of the electrodes are connected to the ends of their re spective autotransformers 5| and 52, and the other ends of these transformers are connected to opposite ends of the out-of-phase starting and regulating reactor 54. The center of these autotransformers 5i and 52 are indicated at 55 and 56, respectively, and the line taps are indicated at 51 and 58, respectively; these taps being 5 to 10% off center.

The tap 51 connects with the line wire 59 and the other tap with the line wire 50 which has inserted therein the regulator 51. To provide suitable voltage and current, an autotransformer may be employed across the lines 59 and 60 as in the other showings.

It is to be noted, that in this instance the lamp autotransformers 5| and 52 are connected in series, not staggered, with respect to their voltage taps, but their primaries are split series connected through a reactance 54 which gives the lag component in the regulating circuit.

It is, of course, understood that various changes and modifications may be made in the details of form, style, design, and construction of the whole or any part of the specifically described embodiment of this invention without departing from the spirit thereof in that such changes and modifications are considered as being within the scope of the following claims.

I claim:

1. In an electrical circuit for starting and maintaining space discharge lamps and the like; a pair of space discharge lamps, each lamp having an electrode at each end thereof, each electrode having a pair of end leads which extend exteriorly of its respective lamp to present a pair of terminals, each lamp having one electrode terminal connected to one of the terminals of its ther electrode through an automatic starter switch; a first autotransformer with end terminals and having an off-center tap, the end terminals of this transformer having connection across a pair of other electrode terminals from different lamps, a second autotransformer having an off-center tap and having end terminals which have connection with still other electrodes through choke coils in parallel which coils have their secondaries shorted, a main autotransformer with a variable intermediate tap and its ends connected in series with leads extending from the off-center taps, and feeder conductors connected across the variable tap and one end of the main transformer which are adapted to be connected to a suitable source of electrical current.

2. The electrical circuit recited in claim 1 wherein the off-center taps are from 5 to off true center coil position.

3. In a circuit for starting and maintaining space discharge types of lighting units; the circuit including a main transformer provided with end terminals and an intermediate terminal, a pair of lighting units consisting of first and second space discharge lamps, each lamp having an electrode at each end thereof and each electrode having a pair of exterior terminals; a first autotransformer and a second autotransformer, each having end terminals and an intermediate offcenter terminal, a pair of choke coils each having their secondaries shorted and the primaries of which are connected in series on opposite sides of the first autotransformer, the other ends of these choke coils having connection with one electrode terminal of each lamp, means including a starter switch connecting the electrode terminals at opposite ends of the first lamp and other means including a starter switch connecting the end electrodes of the second lamp, and means connecting one electrode terminal of each lamp with the second autotransformer so that the autotransformers, choke coils, electrodes and switches are in series connection, and conductors connecting the off-center terminals with the opposite end terminals of the main transformer which supplies the electric current.

4. The circuit recited in claim 3 wherein the off-center terminals are 5 to 10% off true center position.

5. In a circuit for starting and maintaining the illumination of space discharge lamps; the circuit comprising a main current supply transformer with terminals in connection with the load and having terminals for connection to a source of electrical energy; first and second space discharge lamps having end electrodes, an automatic starter means for each lamp, each starter means having conductors making connection in series with one side of its respective electrodes, a first and a second autotransformer each having end terminals with an intermediate terminal connected therein at an off-center electrical position, a pair of reactors in series with the first autotransformer and connected to opposite ends thereof, the other ends of the reactors having connection with electrode terminals of different lamps, the second autotransformer having its end terminals connected to the electrode terminals of different lamps so that the autotransformers, reactors, switches and electrodes have a series connection with each other for starting purposes until after the lamps have been energized when the switches are automatically opened.

6. The circuit recited in claim 5 wherein the intermediate terminals of the autotransformers are set as much as 10% from the reactance centers thereof.

\ WILLARD C. HALL.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,025,471 Osborne Dec. 24, 1935 2,314,311 Karash Mar. 16, 1943 2,358,810 Karash Sept. 26, 1944 2,382,012 Keiser Aug. 14, 1945 

